For many years, hatch adjusters have been in widespread use to hold up hatch covers and deck hatches. Typically, they include a pair of telescoping tubes of various cross sections, preferably round, that slide one inside of another. Their lengths are then determined by varying the distance between the attachment points when the hatch is opened or closed.
Another form of hatch adjuster incorporates a relatively thick spring that is designed to fold in half when the hatch is in the closed position. In such adjusters there is normally no adjustment in length and the length of the spring and its attachment points determine the position of the opened hatch. It is possible that the spring could be mounted on a track to make the open position adjustable, but it is presently believed that this approach is overly complicated.
The spring adjuster does have one advantage. For example, to close the hatch, you push on the middle of the spring to force the spring out of column and cause it to bend. This makes closing easy and fast. However, the disadvantage is that if a hatch assembly is fitted with a single spring adjuster and the spring is accidentally bumped, the hatch cover will fall down and possibly cause severe bodily injury. To alleviate this problem, two adjusters are typically fitted to the assembly. Then it is necessary that both springs be bent to close the hatch.
When a hatch needs to open more than 90.degree.but less than 130.degree. any of the above adjusters may be used. However, when the cover has to rotate through 180.degree. an added problem is introduced. In such cases, the lower end of the adjuster strikes the frame unless it has an appropriate bend. For example, a boat hatch with an adjuster that permits 180.degree. rotation is disclosed in the U.S. Pat. No. 3,976,024. Incorporating bends in the adjuster may weaken the adjuster and at the same time causes the arm to protrude into the hatch opening by several inches. This protrusion into the cabin adversely affects headroom and prevents the attachment of a screen to be fitted up in the hatch cavity.
Accordingly, it is presently believed that there is a large commercial market for an improved hatch assembly as disclosed herein. There should be a relatively large market because the assemblies include an adjuster that permits 180.degree. rotation of the hatch cover, are relatively safe i.e. less likely to be inadvertently or accidentally closed and do not adversely impact the headroom in the cabin of a vessel. It is also believed that the improved hatch assembly in accordance with the present invention can be manufactured, sold and installed at a competitive price. Such assemblies are also durable and allow a hatch cover to be fixed at an opened position at almost any angle of up to 180.degree.. Such covers also overcome the likelihood of the cover being inadvertently or accidentally slammed shut.